Final Diagnosis -- Cavernous hemangioma

FINAL DIAGNOSIS

PULMONARY CAVERNOUS HEMANGIOMA

DISCUSSION

Hemangiomas account for 7% of all benign tumors and are among the most common neoplasms in infants and children, whereas their number in adults is much smaller. They are most commonly seen in the head and neck region and are usually classified based on their clinical appearance and the caliber of the vessels involved.

Cavernous hemangioma, a relatively uncommon variant, is histologically composed of dilated blood-filled spaces supported by scant connective tissue. Although it can occur throughout the body, it rarely occurs as a primary tumor of the lung. To date, approximately 26 cases of pulmonary cavernous hemangioma have been reported. The way in which cavernous hemangiomas present has varied significantly in reported cases. Most cases were identified incidentally on imaging studies for other indications. In the symptomatic cases, the most common symptom was hemoptysis or bloody sputum. Others presented clinically with respiratory distress or cyanosis. While most cavernous hemangiomas are clinically benign, complications such as massive bleeding make recognition of this lesion important in the differential diagnosis of pulmonary masses. These rare tumors can be associated with hereditary telengiectasia and arterio-venous malformations.

Surgery and/or close radiographic follow-up remain the treatment of choice for pulmonary cavernous hemangiomas. The preoperative diagnosis is difficult because pulmonary biopsy is often non-diagnostic as in our case. There is also a risk of bleeding after fine needle or bronchoscopic biopsy. If a tumor is diagnosed as such intraoperatively, wedge resection or enucleation is favored because of its benign behavior.

Other entities to consider in the differential diagnosis considering the patient's age, clinical history, and symptoms include the following.

In infants and young children, intracystic hemorrhage within a congenital pulmonary airway malformation may be mistaken as a vascular lesion. Pulmonary arteriovenous malformations seen in Osler-Weber-Rendu syndrome are also detected in this population, while intrapulmonary hematomas associated with birth trauma may be suspected in the first days of life.

In older children and adults, Kaposi sarcoma, angiosarcoma, and epithelioid hemangioendothelioma must be excluded. While all of these conditions tend to present as multiple pulmonary nodules, specific clinical and histologic features may help in distinguishing these tumors:

Kaposi sarcoma usually occurs in immunocompromised patients and is characterized by a spindle cell proliferation with mild to moderate nuclear atypia and a low mitotic rate surrounding vascular slits filled with extravasated red blood cells. In the lung, Kaposi sarcoma may grow around large blood vessels or display a lymphangittic distribution with widening of interlobular septa.

Angiosarcomas of the lung are rare, and, if found, metastatic disease should be excluded. Histologically, angiosarcoma is characterized by atypical cells lining anastomosing vascular channels. While the sheetlike pattern of growth observed in high-grade lesions makes differentiation easier, rare cases with widely dilated anastomosing spaces mimicking cavernous hemangioma have been reported. In these latter cases, cellular atypia is the key feature for making the diagnosis.

Epithelioid hemangioendothelioma is characterized by proliferation of round to oval cells with abundant eosinophilic cytoplasm and large nuclei in a myxoid or hyaline stroma. Although epithelioid hemangioendothelioma may exhibit tumor cells with large intracytoplasmic vacuoles, these spaces should not be confused with the expanded vascular channels identified in cavernous hemangioma.